Any firefighting equipment that is carried in addition to the minimum required must（）.

单项选择题Any extinguishing agent used on a Class C fire must have which important property?（）

A.Cooling ability
B.Leaves no residue
C.Penetrating power
D.Nonconductivity

单项选择题An inert gas system on a tanker should be used to（）.

A.prevent the generation of flammable or combustible gas in tanks
B.blow out cargo lines to prevent gas concentrations
C.dilute tank atmospheres to keep gas concentrations below the lower explosive limit
D.prevent fires in the pumproom by continually displacing flammable vapors

单项选择题An inert gas system is designed to reduce the possibility of tank explosions by（）.

A.eliminating sparks and fire in the vicinity of cargo tanks
B.removing all hydrocarbon gases from the cargo tanks
C.blanketing cargo tanks with inert foam
D.reducing the oxygen concentration below levels necessary for combustion

单项选择题An important step in fighting any electrical fire is to（）.

A.stop ventilation
B.stop the vessel
C.de-energize the circuit
D.apply water to extinguish the fire

单项选择题An extinguishing agent which effectively cools，dilutes combustible vapors，removes oxygen，and provides a heat and smoke screen is（）.

A.carbon dioxide
B.Halon 1301
C.dry chemical
D.water fog